Cynodon dactylon plant named ‘Oz-E-Green’

ABSTRACT

An asexually reproduced new variety of  Cynodon dactylon  with a unique combination of morphological characters including superior turf performance characterized by dense prostrate habit, slow rate of lateral spread, short internode length, low numbers of inflorescences and inflorescence spikes, and a dark green colour.

FIELD OF INVENTION

The present invention relates to a new and distinct variety of Cynodondactylon (L.) Pers plant, botanically known as Cynodon dactylon, andhereinafter referred to by the variety name ‘Oz-E-Green’.

Cynodon dactylon is a member of the grass family and has common names ofBermudagrass in the United States and green couch grass in Australia. Itis typical for this species to be used for turf. ‘Oz-E-Green’ hasdemonstrated high turf quality and is useful for golf course fairways,tees, residential and commercial lawns, sports fields, recreationalareas, such as parks, and other similar applications.

BACKGROUND OF THE INVENTION

The new ‘Oz-E-Green’ is a unique chance seedling or a spontaneous mutantdiscovered by the Inventor in 2001 in the fringes of a cultivated turfarea of ‘Queensland’ blue couch (Digitaria didactyla) near Childers,Queensland, Australia. The fringe area included ‘Common’ green couch(Cynodon dactylon), but the new variety stood out as being verydifferent from the surrounding green couch and the cultivated bluecouch. Having demonstrated superior turf characteristics, a selectedpiece of sod was removed, broken into vegetative sprigs and propagated.Asexual reproduction of the new variety by vegetative sprigs since 2001,in the nursery area of the turf farm where it was discovered nearChilders, Queensland, Australia, has shown that the unique features ofthis new Cynodon dactylon variety are stable and reproduced true to typein six successive generations.

As ‘Oz-E-Green’ is very short in vertical growth height, even when notmown for an extended period, ‘Plateau’, ‘TL1’ and ‘Riley's Super Sport’were identified as being lower growing varieties than other Cynodondactylon cultivars and may be considered to be the most similarvarieties.

‘Plateau’ is disclosed in U.S. Plant Pat. No. 13,059 and Australian PBRNo. 1439. ‘Riley's Super Sport’ is disclosed in U.S. Plant Pat. No.11,181 and Australian PBR No. 739 and ‘TL1’ is disclosed in AustralianPBR No. 2638.

SUMMARY OF THE INVENTION

Plants of the variety ‘Oz-E-Green’ have not been observed under allpossible environmental conditions. The phenotype may vary somewhat withvariations in environment such as temperature, light intensity and daylength without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘Oz-E-Green’. These characteristics incombination distinguish ‘Oz-E-Green’ as a new and distinct cultivar:

-   -   1. very prostrate growth habit (i.e. having a very short        vertical growth height),    -   2. fine leaf texture,    -   3. short internode length,    -   4. slow lateral extension growth rate,    -   5. forms a dense mat,    -   6. low numbers of inflorescences,    -   7. low number of spikes per inflorescence,    -   8. short spike length, and    -   9. dark green colour (RHS N138B).

Other significantly different features demonstrated from the comparativegrowing trial are described herein. Advantageously these properties maydirectly relate to the selection criteria of the new variety of‘Oz-E-Green’, which was based on dense prostrate habit, limitedinflorescence production (contributing to a low mowing requirement),high turf quality, and attractive dark green colour.

The new variety is propagated vegetatively (asexual reproduction) bysod, plugs, sprigs, tillers, rhizomes or stolons. Vegetative propagationhas established that the characteristics have been passed through sixgenerations without showing any discernible off types.

The putative parent ‘Common’ green couch (or common Bermudagrass as itis known in the United States) was observed in the region of thediscovery site of the new variety near Childers, Queensland, Australia,where it was in the vicinity of ‘Oz-E-Green’ growing in the fringe of acultivated turf growing area of ‘Queensland’ blue couch. ‘Common’ greencouch was considered to be so different to ‘Oz-E-Green’ that it was notconsidered to be pertinent at all to comparative trials by the inventorand the qualified person who conducted the trials.

‘Common’ green couch has coarser textured leaves and stems, more openand erect growth (does not form a dense mat in comparison to the newvariety), profuse inflorescence production, more spikes perinflorescence, longer inflorescence spikes, and a lighter green leafcolouring. It also spreads laterally more rapidly than the ‘Oz-E-Green’.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a comparison of the new variety ‘Oz-E-Green’ to ‘Plateau’,‘TL1’ and ‘Riley's Super Sport’, and

FIG. 2 shows the turf appearance of the new variety.

DETAILED BOTANICAL DESCRIPTION

Latin name of the genus and species of the plant claimed: The presentinvention relates to the genus and species Cynodon dactylon (L.) Pers.

Variety denomination: ‘Oz-E-Green’.

Plants of the variety ‘Oz-E-Green’ have not been observed under allpossible environmental conditions. The phenotype may vary somewhat withvariations in environment such as temperature, light intensity and daylength without, however, any variance in genotype.

1. Origin and Breeding

‘Oz-E-Green’ is a new variety of Cynodon dactylon which is suitable foruse as turf in all areas, and in particular to golf course fairways,tees, residential and commercial lawns, sports fields, playing areas andthe like. ‘Oz-E-Green’ is a spontaneous mutation or a chance seedlingdiscovered in an area where there was ‘Common’ green couch and locatedon the fringe of a cultivated turf area of ‘Queensland’ Blue Couch(Digitaria didactyla) near Childers, Queensland, Australia in 2001.Given the location of ‘Oz-E-Green’, it is assumed ‘Common’ green couchmay be the putative parent. Cynodon dactylon is considered to begenetically stable so it more likely ‘Oz-E-Green’ is a chance seedling.However spontaneous mutation was also considered as an option for theorigin of ‘Oz-E-Green’ due the significantly differing plantcharacteristics.

The cultivated turf area of ‘Queensland’ blue couch was unfertilized atthe time making it easier to locate contaminant grasses in the turf areaand fringes for the purpose of spot spraying for quality assurance. Thenew variety was discovered in the fringes by the Inventor as beingsubstantially different to other ‘Common’ green couch grasses displayingthe potential characteristics that would be advantageous for turfperformance. ‘Oz-E-Green’ was then marked for further observation.

Having been observed for a short period, ‘Oz-E-Green’ demonstratedsuperior turf characteristics and a selected piece of sod was removed.It was broken apart and washed to ensure there were no impurities andvegetative sprigs were removed to propagate a larger area of thisvariety elsewhere on the breeder's property. The original selected planthas been vegetatively propagated in six successive generations withoutshowing any discernible off types and has remained true to typedemonstrating distinctiveness, uniformity and stability. The selectioncriteria for ‘Oz-E-Green’ were that it had a dense prostrate habit,limited inflorescence production (giving a low mowing requirement), highturf quality, and dark green colour.

2. Characteristics

The description of the variety is taken from comparative trialsconducted between Aug. 24, 2003 to Mar. 16, 2004 in Cleveland,Queensland, Australia (Latitude 27°32′ South, Longitude 153°15′ East,elevation 25 masI). The soil type was a ferrosol (Isbell, R.F. (2002)‘The Australian Soil Classification’. Revised Edition. CSIRO Publishing,Collingswood, Victoria, Australia). The characteristics of the newvariety are as follows with all R.H.S. Colour Chart numbers referring to2001 edition.

-   Classification: Cynodon dactylon (L.) Pers. ‘Oz-E-Green’.-   Parentage: Putative parent is ‘Common’ green couch as commonly known    in Australia or ‘Common’ Bermudagrass as it is commonly know in the    United States.-   Propagation: Vegetatively (asexual reproduction) by sod, plugs,    sprigs, tillers and pieces of rhizomes or stolons.-   Growth habit: Habit creeping, type tight mat-forming, height very    short, longevity perennial, spreading laterally by stolons and    rhizomes.-   Leaf blade: Shape linear-triangular, length medium-short, width    medium.-   Vegetative leaf: In the comparative trials, the 4^(th) youngest    visible node was used as the standard for the leaf measurements as    it was considered that no further leaf blade expansion is likely and    senescence or other forms of destruction or deterioration (such as    by insects, disease, etc) is unlikely to have occurred.    -   -   Blade length range.—Mean tiller 4th leaf blade length is            28.2 mm. (Range 16.4-43.0 mm). Mean stolon 4th leaf blade            length is 8.6 mm. (Range 4.2-17.9 mm).        -   Blade width mean.—Mean tiller 4th leaf blade width 2.09 mm.            Mean stolon 4th leaf blade width 2.30 mm.        -   Sheath length mean.—Mean tiller 4th leaf sheath length            10.29 mm. Mean stolon 4th leaf sheath length 7.7 mm.-   Stolon: Compound nodes with up to 3 leaves, internode length short,    internode thickness medium, colour grey-brown (RHS N199B) when    exposed to sunlight.-   Ligule: Dense row of short white hairs.-   Inflorescence: Digitate with (3-)4 short spicate racemes.    -   -   Culm.—Length very short.        -   Peduncle.—Length very short — mean length 65.6 mm and mean            diameter 0.51 mm.        -   Spike length.—Mean length 25.2 mm.        -   Flag leaf blade length.—Mean length 16.1 mm.        -   Flag leaf blade width.—Mean width 1.79 mm.-   Color notations:    -   -   Leaf blade color adaxial leaf surface.—Dark green RHS N138B            (summer).        -   Stolon color.—RHS N199B (summer, exposed to sunlight).-   Disease susceptibility: From observations of Oz-E-Green in a    cultivated environment, it was noted the new variety is not as prone    to fungus, bacteria and rot to the plant stems or stolons from    thatch or clippings that falls on top of the turf in comparison to    ‘Common’ green couch.    3. Comparative Trials

The grouping characteristics used in identifying the most similarvarieties of common knowledge was creeping habit, mat-forming type andvery short height. ‘Plateau’^(A), ‘TL1’^(A) and ‘Riley's SuperSport’^(A) are lower growing than other Cynodon dactylon cultivars andtherefore considered to the most similar varieties. This selection wasbased on their growth in a world collection of 138 turf grasses andgeneral knowledge of the persons conducting the trial.

The putative parent ‘Common’ green couch was excluded because it isreadily distinguishable from ‘Oz-E-Green’ by its coarser, more open anderect growth, and lighter green leaves.

On Aug. 24, 2003, 5 cm cores were planted spaced apart 1 m×1 m. Theplants were not defoliated and weed control was by pre-emergenceoxidation. Nutrition was maintained with slow release fertilisers. Theexperimental design of the trial involved 30 plants per variety with 5plants per plot in 6 randomised blocks. Two measurements were taken perplant. The diameter of spread measurements was take on Nov. 21, 2003,stolon leaf and internode measurements were taken on Dec. 17-18, 2003,shoot and inflorescence measurements were taken on Dec. 18, 2003-Jan.12, 2004 and leaf and stolon colour on Mar. 16, 2004 on the spacedplants. The results of the comparative trials are shown in Table 1 belowcalculated to a significance of 1%. FIG. 1 illustrates distinctivefeatures of the new variety.

Referring to Table 1, it is evident from the substantial variation inthe measurements that TL1 has significantly different morphologicalcharacteristics than ‘Oz-E-Green’, ‘Plateau’ and ‘Riley's Super Sport’despite being low growing. For example, when compared to the threevarieties ‘TL1’ is the slowest growing grass as indicated by the meandiameter of spread on the spaced plants. It also has the shortestinternodes and the shortest stolon leaf blade length, but the longestleaf blade length indicating that it is more coarse textured than theother cultivars in the trial. These differences are illustrated in FIG.1 which clearly shows the dissimilar morphology to ‘Oz-E-Green’.

Compared to ‘Plateau’ and ‘Riley's Super Sport’, ‘Oz-E-Green’ is slowerto spread laterally as shown by the mean plant diameter of the spacedplants after 89 days. Similarly, the length of the fourth internode on‘Oz-E-Green’ was the shortest. Its relatively slow lateral growth andshort stolon internodes indicate that ‘Oz-E-Green’ forms a tight mat.This is especially so compared to ‘Riley's Super Sport’ which had thelongest stolon internodes and was the fastest spreading. Anotherdifference is that the new variety has thinner stolons.

‘Oz-E-Green’ produced fewer spikes than both of the comparatorvarieties. This indicates a lower mowing requirement which in particularwould be advantageous in large areas of turf that require highmaintenance such as a golf course. When produced, the inflorescencespikes of ‘Oz-E-Green’ are longer than ‘Plateau’ but shorter than‘Riley's Super Sport’ and the peduncle length is significantly longerthan the comparators.

The leaf texture of the new variety is fine and similar to the texturesof the two comparator varieties. Stolon leaf blades on ‘Oz-E-Green’ arenot significantly different in length to those of ‘Plateau’ and ‘Riley'sSuper Sport’, but are significantly narrower than on ‘Plateau’ as alsoshown by the greater length:width ratio. The length of stolon leafsheaths on ‘Oz-E-Green’ is also shorter than on the two comparators.

In unmown swards, the flag leaf blades on flowering tillers of‘Oz-E-Green’ are significantly longer than on ‘Plateau’, while the flagleaf blades are significantly and wider than those of ‘Plateau’ and‘Riley's Super Sport’. The leaf sheaths on flowering tillers of‘Oz-E-Green’ are significantly shorter than on ‘Riley's Super Sport’.

Other differences are evident from the comparative data presented inTable 1.

The new and distinct variety ‘Oz-E-Green’ is an excellent quality turfgrass variety of Cynodon dactylon having distinguishing features fromlow growing ‘Plateau’, ‘Riley's Super Sport’ and ‘TL1’ and ‘Common’Bermudagrass.

The ligule consists of a dense row of short hairs about 0.2 to 0.5 mmlong on a membranous rim with longer hairs about 1.0 to 1.5 mm long ateach end. The leaf blades are flat or slightly V-shaped,linear-triangular in shape, about 2.5 to 3.5 mm long, about 2.0 mm wide,pointed, glabrous or very sparsely pubescent both on the upper (adaxial)surface and on the lower (abaxial) surface, minutely scabrous on themargin. Auricles are absent. The sheath is glabrous, split with marginsoverlapping. The collar is a continuous narrow band. Leaves are foldedin the bud shoot, with vernation conduplicate.

Culms are decumbent to erect, about 20 to 80 mm long and about 1.0 to2.0 mm wide. The term “flag leaf” is used to refer to the highest leafon a flowering culm, immediately below the inflorescence.

The inflorescence is digitate with (3-)4 short spicate racemes about20-30 mm long, peduncles are short, about 50-80 mm long. The rhachis isflattened, with spikelets packed broadside to rhachis, regular, 2-rowed.

Spikelets are appressed, solitary. Fertile spikelets are at least3-flowered, comprising 1 fertile floret, without rhachilla extension,ovate, laterally compressed, 1.8-3 mm long, breaking up at maturity.Spikelets disarticulate below each fertile floret.

Glumes are persistent, similar, subequal in width, thinner than thefertile lemma. The lower glume is lanceolate and equal to the upperglume, herbaceous, 1-keeled, 1-nerved. Lateral nerves are absent in boththe upper and the lower glumes. The apex on both the upper and the lowerglumes is acute. The upper glume is lanceolate, 50-80% of the length ofthe adjacent fertile lemma, herbaceous, 1-keeled, 1-nerved.

The fertile lemma is ovate, laterally compressed, 1.8-3 mm long,cartilaginous, wingless, 3-nerved. Lemma midnerve pubescent. Lemma apexacute. Palea 2-nerved. Palea keels eciliate. Anthers 1-1.2 mm long.Anthers and stigmas purple. Grain (caryopsis) with adherent pericarp,ellipsoid, laterally compressed.

TABLE 1 *‘Riley's ‘Oz-E-Green’ *‘Plateau’^(A) *‘TL1’ Super Sport’^(A)MEAN PLANT DIAMETER OF SPACED PLANTS AFTER 89 DAYS (cm) mean 70.9 95.339.6 134.2 std deviation 29.7 26.5 11.6 37.1 LSD/sig 24.9 ns P ≦ 0.01 P≦ 0.01 FIRST STOLON NODE WITH SECOND LATERAL BRANCH (mm) mean 0.98 0.921.27 0.75 std deviation 0.29 0.38 0.48 0.44 LSD/sig 0.163 ns P ≦ 0.01 P≦ 0.01 LENGTH OF FOURTH INTERNODE FROM STOLON TIP (mm) mean 31.7 37.619.4 52.1 std deviation 5.1 3.7 3.5 6.5 LSD/sig 2.7 P ≦ 0.01 P ≦ 0.01 P≦ 0.01 DIAMETER OF FOURTH INTERNODE FROM STOLON TIP (mm) mean 1.69 1.771.69 1.84 std deviation 0.16 0.16 0.10 0.18 LSD/sig 0.08 P ≦ 0.01 ns P ≦0.01 LENGTH OF LEAF SHEATH ON FOURTH VISIBLE NODE FROM STOLON TIP (mm)mean 7.7 10.4 5.7 13.0 std deviation 1.1 1.6 0.9 1.4 LSD/sig 0.9 P ≦0.01 P ≦ 0.01 P ≦ 0.01 LENGTH OF LEAF BLADE ON FOURTH VISIBLE NODE FROMSTOLON TIP (mm) mean 8.6 7.2 6.6 9.1 std deviation 3.0 1.5 1.6 3.0LSD/sig 1.9 ns P ≦ 0.01 ns WIDTH OF LEAF BLADE ON FOURTH VISIBLE NODEFROM STOLON TIP (mm) mean 2.30 2.66 3.14 2.21 std deviation 0.31 0.270.33 0.36 LSD/sig 0.22 P ≦ 0.01 P ≦ 0.01 ns LENGTH:WIDTH RATIO OF LEAFBLADE ON FOURTH VISIBLE NODE FROM STOLON TIP mean 3.69 2.70 2.12 4.07std deviation 0.99 0.51 0.53 1.02 LSD/sig 0.59 P ≦ 0.01 P ≦ 0.01 nsLENGTH OF SHEATH ON FLAG LEAF ON FLOWERING TILLERS (mm) mean 35.6 36.131.4 42.6 std deviation 7.1 7.7 5.0 5.4 LSD/sig 4.9 ns ns P ≦ 0.01LENGTH OF BLADE ON FLAG LEAF ON FLOWERING TILLERS (mm) mean 16.1 8.5 5.014.9 std deviation 6.7 4.4 2.6 5.4 LSD/sig 3.1 P ≦ 0.01 P ≦ 0.01 nsWIDTH OF BLADE ON FLAG LEAF ON FLOWERING TILLERS (mm) mean 1.79 1.401.20 1.50 std deviation 0.29 0.37 0.34 0.31 LSD/sig 0.21 P ≦ 0.01 P ≦0.01 P ≦ 0.01 LENGTH:WIDTH RATIO OF FLAG LEAF BLADE ON FLOWERING TILLERSmean 8.84 5.82 4.06 9.89 std deviation 3.02 1.90 1.40 2.75 LSD/sig 1.74P ≦ 0.01 P ≦ 0.01 ns LENGTH OF SHEATH ON FOURTH LEAF ON FLOWERINGTILLERS (mm) mean 10.29 10.18 10.40 12.47 std deviation 1.85 2.40 2.032.64 LSD/sig 1.742 ns ns P ≦ 0.01 LENGTH OF BLADE ON FOURTH LEAF ONFLOWERING TILLERS (mm) mean 28.2 20.7 17.7 31.1 std deviation 6.3 6.96.4 6.7 LSD/sig 5.5 P ≦ 0.01 P ≦ 0.01 ns WIDTH OF BLADE ON FOURTH LEAFON FLOWERING TILLERS (mm) mean 2.09 2.32 2.09 2.07 std deviation 0.280.34 0.36 0.21 LSD/sig 0.249 ns ns ns LENGTH:WIDTH RATIO OF FOURTH LEAFBLADE ON FLOWERING TILLERS mean 13.59 8.84 8.49 15.17 std deviation 3.142.47 2.84 3.53 LSD/sig 2.17 P ≦ 0.01 P ≦ 0.01 ns LENGTH OF PEDUNCLE ONFLOWERING TILLERS (mm) mean 65.6 41.9 36.2 51.6 std deviation 14.4 8.76.9 9.8 LSD/sig 12.3 P ≦ 0.01 P ≦ 0.01 P ≦ 0.01 DIAMETER OF PEDUNCLE ONFLOWERING TILLERS (mm) mean 0.51 0.52 0.51 0.53 std deviation 0.06 0.090.07 0.09 LSD/sig 0.06 ns ns ns AVERAGE LENGTH OF SPIKES (mm) mean 25.226.5 21.9 33.0 std deviation 2.9 5.4 3.1 5.2 LSD/sig 3.3 ns P ≦ 0.01 P ≦0.01 NUMBER OF SPIKES PER INFLORESCENCE mean 3.60 3.90 4.08 3.95 stddeviation 0.50 0.57 0.33 0.29 LSD/sig 0.30 P ≦ 0.01 P ≦ 0.01 P ≦ 0.01MAXIMUM NUMBER OF SPIKES PER INFLORESCENCE 4 5 5 5 STOLON COLOUR EXPOSEDTO SUNLIGHT (RHS, 2001) N199B N199B N199A N199A LEAF COLOUR (RHS, 2001)N138B 147A 147A N138B

1. A new and distinct variety of Cyondon dactylon plant, substantiallyas described and illustrated herein, characterized particularly by aunique combination of morphological characters.